This post is part of a series that explores some features unique to surgery for cancer. This particular article focuses on the concept of “tumor-free margin” in the context of oncologic surgeries.
A fundamental principle of curative surgery for cancer is to resect (remove) the entire tumor without leaving even the tiniest bit behind (see this article to know the difference between “cancer” and “tumor”).
In my clinical practice, I often give my patients the analogy of a garden with a tree and a stone. A benign tumor is like a stone – if we simply dig out the stone, we are certain that the stone is gone forever. But a malignant (cancerous) tumor is like a tree – it has to be removed along with all its roots – otherwise, it can come back.
The roots of a tree are not visible on the surface of the ground, cancer infiltration into the surrounding tissues may not always be apparent. Roots can be superficial or go really deep depending on the type of tree and the age/size of the tree. Similarly, the type and stage determine how much a particular cancer can “infiltrate” into the surrounding normal tissues.
Thus the extra surrounding normal tissue (“margin”) which needs to be removed can vary from a few millimeters to several centimeters, depending on which organ is affected with cancer, the type of cancer, stage, grade, and sometimes other factors as well.
Optimal resection of cancer is a balance between ensuring tumor-free margins, and at the same time retaining all body tissues that can be safely preserved.